Improvement in coal-screens



s. w. WOODWARD.

Coal-Screens.

Patented April 29. 1873.

Iii

AM PHOTOUTHDGRAFHIC 80. N. X('asszm-s's PRacEss) UNITED STATES- PATENT OFFICE.

STEPHEN W. WOODWARD, OF BUFFALO, NEW YORK.

IMPROVEMENT m COAL-SCREENS.

Specification forming part of Letters Patent No. 138,355, dated April 29, 1873; application filed December 31, 1872. i

To all whom it may concern:

Be it known that I, STEPHEN WALTER WOODWARD, of Buffalo, in the county of Erie and State of New York, have invented certain new and useful Improvements in Screen- Operators for Screening and Sifting Coal- Ashes, Flour, Sand, &c., of which the following is a specification:

This invention relates to screens or sifters for sifting coal, ashes, flour, 8w; and consists in attaching to a wire-cloth or other screen a system of levers, 860-, for form of a toggle or knuckle joint, to oscillate said screen, as hereinafter described.

In the drawing, Figure l is a perspective view. Fig. 2 is a sectional side elevation.

Ais an oblong box, having a shorter box, B, sitting therein. This box B has a wirecloth screen, a, which forms its bottom, and is supported in place by side pieces attached to the inside of the outer box A. These supporting-pieces have small rollers or casters b, (see Fig. 1,) to enable the box B to work more easily in its movement back and forth. Attached to one corner of the outer box A is a pin or rod, 0, which passes through and acts as a guide to bend strip of metal 01, as shown.

One end of this strip d passes through the box A, and is attached loosely to one corner of the screen-box B (see Fig. 2) in such a manner that it can be readily detached to allow the box 13 to be removed, as indicated by dotted lines at e. The other end of this strip d is riveted loosely to a longer strip, f, which, in turn, is riveted, at g, to a similar strip, h,

which is pivoted, at 'i, to the side of box A,

thus forming a toggle or knuckle joint by the bars 7 f and h. It will be readily seen that if these bars are moved up and down by the rivet g, the box Bwill be moved'backward and forward by the strip d.

There is a number of methods by which the bars f and It may be operated. One method is by extending the bar h backward in the form of a handle, as at G, by which means the screen may be readily and easily oscillated. Another method is by means of a crank motion. This I accomplish by attaching to the bars f and h a slotted metal piece, D, shown in Fig. 2, and having small slots k, where it is secured to the bars f and h, to allow of suffi cient play in its motion up and down. E is an upright post or standard secured to the base-piece H of the box A, and having a shaft passing through its top part, carrying two cranks, I and J, the former of which has a slide, m, working loosely in the slot in the piece D, while the latter or shaft J is provided with a handle, a, to operate the device.

The action of this arrangement will be seen at a glance. The cranks, in their revolutions, serve to raise and lower the piece D, which carries with it the bars f and h, and so operates the screen in precisely the same manner as by the handle 0.

The advantages of this arrangement are many. I obtain two oscillations of the screen by only one revolution of the crank on one movement of the lever O, which is a great advantage, causing the screen to do its work in much less time, and by less use of power, as by the arrangement of the levers and bars I obtain a great purchase and a powerful leverage.

For sifting coal-ashes, &c., the box A will be made with a circular strip, 19, attached to its bottom to fit into and hold the box upon a barrel 5 or it may be made with a larger box or reservoir to catch the ashes, 85c.

There are many other methods by which the levers may be operated, but I prefer one of those shown.

It may also be applied to the screens of grain-separating machines.

What I claim as my invention is 1. The toggle-levers f and h, in combination with the bent arm d, slotted piece D, and cranks I J, or their equivalents, for imparting a reciprocating motion to sieve B, substan tially as described.

2. The combination of the bent piece d and screen-box B, when constructed, as shown and described.

In witness whereof I have hereunto signed my name in the presence of two subscribing 

